the locked option isn't a standard printer option - I presume the term you are looking for is 'access controlled printer'.
this link advises you need to modify the driver for epsom printers
So I'm guessing you will need code to update the driver - almost certainly means messing with the windows registry which your IT may or may not allow. Alternatively your IT dept may be able to provide the solution.
Presumably users are able to print excel/word files to these printers as well, so it may already be done, just send the file to print, go to the printer and key in your code. That's how it works at clients of mine who use printer access control.